Switching devices for switching high current to drive high current devices such as an electric motor are well known. Such switch devices include, e.g. Insulated Gate Bipolar Transistors (IGBTs), which are typically controlled by a microprocessor or other digital device to provide desired drive currents to windings of an electric motor. The signals for switching (driving) the IGBTs often require current buffering.
One type of current buffer used to drive an IGBT is a non-inverting bipolar transistor. In other words, the output logic signal of the driver is the same polarity as the output of the current buffer. Additional circuitry (i.e., additional components) is provided to prevent voltage shoot-through as a result of base storage time, as is known. The bipolar transistor also introduces an additional voltage drop (1.4 volts) between the voltage rails and the output, thus requiring a higher voltage bias supply to offset the voltage drop.
Another type of current buffer is a Metal Oxide Silicon Field Effect Transistor (MOSFET), which introduces an inversion of the output of the current buffer. This causes the MOSFETs not to be usable with MOSFET with gate drivers that have built-in fault handling. Additional circuitry is also provided to prevent voltage shoot-through due to mutual conduction of the MOSFETs during the switching time.